eh_globals.cc revision 132720 
1// -*- C++ -*- Manage the thread-local exception globals.
2// Copyright (C) 2001, 2004 Free Software Foundation, Inc.
3//
4// This file is part of GCC.
5//
6// GCC is free software; you can redistribute it and/or modify
7// it under the terms of the GNU General Public License as published by
8// the Free Software Foundation; either version 2, or (at your option)
9// any later version.
10//
11// GCC is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14// GNU General Public License for more details.
15//
16// You should have received a copy of the GNU General Public License
17// along with GCC; see the file COPYING.  If not, write to
18// the Free Software Foundation, 59 Temple Place - Suite 330,
19// Boston, MA 02111-1307, USA.
20
21// As a special exception, you may use this file as part of a free software
22// library without restriction.  Specifically, if other files instantiate
23// templates or use macros or inline functions from this file, or you compile
24// this file and link it with other files to produce an executable, this
25// file does not by itself cause the resulting executable to be covered by
26// the GNU General Public License.  This exception does not however
27// invalidate any other reasons why the executable file might be covered by
28// the GNU General Public License.
29
30
31#include <exception>
32#include <cstdlib>
33#include "unwind-cxx.h"
34#include "bits/c++config.h"
35#include "bits/gthr.h"
36
37using namespace __cxxabiv1;
38
39
40// Single-threaded fallback buffer.
41static __cxa_eh_globals globals_static;
42
43#if __GTHREADS
44static __gthread_key_t globals_key;
45static int use_thread_key = -1;
46
47static void
48get_globals_dtor (void *ptr)
49{
50  if (ptr)
51    std::free (ptr);
52}
53
54static void
55get_globals_init ()
56{
57  use_thread_key =
58    (__gthread_key_create (&globals_key, get_globals_dtor) == 0);
59}
60
61static void
62get_globals_init_once ()
63{
64  static __gthread_once_t once = __GTHREAD_ONCE_INIT;
65  if (__gthread_once (&once, get_globals_init) != 0
66      || use_thread_key < 0)
67    use_thread_key = 0;
68}
69#endif
70
71extern "C" __cxa_eh_globals *
72__cxa_get_globals_fast () throw()
73{
74#if __GTHREADS
75  if (use_thread_key)
76    return (__cxa_eh_globals *) __gthread_getspecific (globals_key);
77  else
78    return &globals_static;
79#else
80  return &globals_static;
81#endif
82}
83
84extern "C" __cxa_eh_globals *
85__cxa_get_globals () throw()
86{
87#if __GTHREADS
88  __cxa_eh_globals *g;
89
90  if (use_thread_key == 0)
91    return &globals_static;
92
93  if (use_thread_key < 0)
94    {
95      get_globals_init_once ();
96
97      // Make sure use_thread_key got initialized.
98      if (use_thread_key == 0)
99	return &globals_static;
100    }
101
102  g = (__cxa_eh_globals *) __gthread_getspecific (globals_key);
103  if (! g)
104    {
105      if ((g = (__cxa_eh_globals *)
106	   std::malloc (sizeof (__cxa_eh_globals))) == 0
107	  || __gthread_setspecific (globals_key, (void *) g) != 0)
108        std::terminate ();
109      g->caughtExceptions = 0;
110      g->uncaughtExceptions = 0;
111    }
112
113  return g;
114#else
115  return &globals_static;
116#endif
117}
118